SK Hynix to Mass-Produce 375-Layer NAND by Year-End, U.S. Stock Listing Could Land as Early as August
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SK Hynix plans to begin mass production of 375-layer 3D NAND at its Cheongju fab by year-end, while its U.S. listing could land as early as August — the SEC may approve the ADR application the week of June 22. This means → the world's second-largest memory chipmaker is compressing a product generation shift and a capital-markets milestone into the same window.
How is SK Hynix building 375-layer NAND?
No new fab lines. SK Hynix is converting existing 176-layer, 238-layer, and 321-layer lines at its Cheongju M15 plant. In plain terms = retrofit the old house instead of building a new one.
The product has cleared production verification and is switching to mass-production status. This reflects a "fast iteration, low capex" playbook rather than a spend-heavy greenfield approach.
The chip was originally codenamed internally as "400-layer class" but was finalized at 375 layers — channel-hole etching (drilling a vertical shaft through hundreds of stacked layers) grows exponentially harder with each added layer, and 375 is the pragmatic ceiling for current process technology.
Why swap tungsten for molybdenum?
The key design change: SK Hynix is introducing molybdenum into the metal gate electrodes (word lines — the internal wires that carry read/write commands) to partially replace tungsten.
This means → as layers increase and lines shrink, tungsten's resistance climbs and signals slow down. Molybdenum has lower resistance at fine line widths, speeds up read/write/erase, and eliminates the barrier liner tungsten deposition requires — freeing space for denser stacking.
After evaluating Lam Research and Tokyo Electron (TEL), SK Hynix chose TEL's furnace-type deposition tool, which processes roughly 100 wafers per batch — an edge in cost and floor-space efficiency.
Who controls the molybdenum supply chain?
Air Liquide, Entegris, and Merck KGaA are expected to supply molybdenum materials to SK Hynix. South Korea's SK Specialty is also in talks but lacks standalone storage and delivery infrastructure.
SK Hynix is pushing SK Specialty to ship via Air Liquide's distribution network. In plain terms = the domestic supplier has the material but not the logistics — it needs to borrow someone else's truck.
Industry estimates: Samsung's molybdenum purchases were about 4 tonnes last year, rising to roughly 10 tonnes this year and potentially 80 tonnes by 2030. SK Hynix's initial consumption starts at about 4 tonnes/year once large-scale use begins next year. This reflects molybdenum's shift from niche metal to strategic memory-chip material.
What is the core logic behind SK Hynix's NAND strategy?
The goal is not to expand total capacity but to raise bit-output efficiency — cut low-layer products, fill the gap with 375-layer chips, and drive down unit cost.
An industry source said: "Unlike DRAM, the NAND industry today cares more about profitability than shipment volume." This means → in an oversupplied NAND market, stacking margins beats stacking capacity.
In plain terms = the same wafer stores far more data at 375 layers, so cost per bit drops — the value of 375 layers is not "more chips" but "cheaper bits."
What supports a threefold capacity expansion?
SK Group Chairman Chey Tae-won told Nikkei Asia that SK Hynix's wafer capacity is expected to triple by 2034. "It doubles in five years, but once all the facilities are built, by around 2034 it's not just double — it's triple."
Four new fabs are under construction in Yongin, with the first phase due for completion early next year. The overall timeline has been pulled forward by roughly ten years from the original 2045 target.
After completing domestic facilities, the next step is overseas expansion — Japan is a priority, citing its complete semiconductor ecosystem: power, clean water, engineers, and chemical suppliers.
Where does the U.S. listing stand?
Reuters, citing two sources, reports the SEC may approve SK Hynix's ADR application the week of June 22, with a U.S. listing possible as early as August.
This means → if on schedule, SK Hynix would become the next major Korean memory chipmaker listed in the U.S. after Samsung, directly tapping American investors' semiconductor allocation demand.
Chairman Chey expressed confidence in long-term AI infrastructure demand, expecting the market to expand from enterprise procurement to consumer-facing agentic AI services. 375-layer mass production, ADR listing, and a threefold capacity ramp — whether SK Hynix can deliver on all three simultaneously will be the defining test of its strategic execution.
Content is for reference only, not financial advice.